How to do a Decay Chain of Length 3 in Madspin

Asked by Jason Gombas

Dear Experts,

I am currently running Madgraph at NLO and am using a BSM model that includes a W'. I am generating events with the following command:

generate p p > t~ wp+ NP<=1 QED<=0 [QCD]

I then wish to decay wp+ using Madspin. In the Madspin card I added the line:

decay wp+ > t b~, t > w+ b, w+ > all all

However, after Madgraph completes its run, I inspect the .lhe file in the decayed directory. Here I have copied a sample event from the .lhe file, and you can see that the W+ (24) is not decayed.
(I have omitted the energy and momentum data for readability)

       21 -1 0 0 501 502
       21 -1 0 0 503 501
       -6 2 1 2 0 502
       -5 1 3 3 0 502
      -24 2 3 3 0 0
        3 1 5 5 504 0
       -4 1 5 5 0 504
       34 2 1 2 0 0
       -5 1 8 8 0 505
        6 2 8 8 505 0
        5 1 10 10 505 0
       24 1 10 10 0 0
        5 1 1 2 503 0

I am wondering if I am not using the correct syntax in Madspin for this decay chain of length 3, or if this is not possible to do this in Madspin?

Thanks for your help!
Jason

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MadGraph5_aMC@NLO Edit question
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Solved by:
Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said :
#1

The correct syntax is

decay wp+ > t b~, (t > w+ b, w+ > all all)

Cheers,

Olivier

Revision history for this message
Jason Gombas (gombasja) said :
#2

Thanks! This has answered my question.